Fastener

ABSTRACT

A fastener comprising a first piece having a head portion and a hollow sleeve extending therefrom, a through-bolt affixed to said first piece extending from within said sleeve portion, the through-bolt having a peripheral recessed groove formed therein, a second hollow piece comprising a head having a sleeve integrally formed therewith, wherein the sleeve portion of said second piece surrounds a portion of said through-bolt and extends toward the sleeve of said first piece such that when said second piece is forced to move relative to said first piece on said through-bolt the sleeve portion of said first piece deforms the sleeve of said second piece into the peripheral groove.

United States Patent [191 Swindt, II

[451 Nov. 13, 1973 Primary ExaminerRamon S. Britts vAtt0rneySokolski & Wohlgemuth [57] ABSTRACT A fastener comprising a first piece having a head portion and a hollow sleeve extending therefrom, a through-bolt affixed to said first piece extending from within said sleeve portion, the through-bolt having a peripheral recessed groove formed therein, a second hollow piece comprising a head having a sleeve integrally formed therewith, wherein the sleeve portion of said second piece surrounds a portion of said throughbolt and extends toward the sleeve of said first piece such that when said second piece is forced to move relative to said first piece on said through-bolt the sleeve portion of said first piece deforms the sleeve of said second piece into the peripheral groove.

9 Claims, 9 Drawing Figures FASTENER [75] Inventor: Joseph K. Swindt, II, Manhattan Beach, Calif.

[73] Assignee: VSI Corporation, Pasadena, Calif.

[22] Filed: May 1, 1972 [21] App]. No.: 249,685

[52] [1.8. CI ..8S/1R, 85/4, 85/70, 85/79, 52/758F [51] Int. C1.Fl6b 5/01, F16b 13/06, F1613 19/10 [58] Field of Search 287/189.36 D, 189.36 F,

[56] References Cited UNITED STATES PATENTS 2,030,170 2/1936 Huck 85/70 2,974,558 3/1961 Hodell 3,078,002 2/1963 Rodgers 3,322,449 5/1967 Becker 85/70'X 37 f ,7 ll

PATENTEnuuvm 1975 3,771,410 SHEET 10F 3 FIG. 15

INVENTOR.

JOSEPH KEENER SW/NDTIZ' SOKOLSK/ 8 WOHLGEMUTH ATTORNEYS PATENTEUHUY 13 ms 3.771.410

sum 2 0r 3 I N VENTOR.

JOSEPH KEENER SWINDTIZ' SOKOLSK/ 8 WOHLGEMUTH ATTORNEYS PATENTEDHUY 13 1975 SHEET 30F 3 FIG. 3

FIG. 4

FIG. 5

INVENTOR.

JOSEPH KEENER SW/NDTlI SOKOLSK/ 6 WOHLGEMU TH ATTORNEYS FASTENER CROSS REFERENCE TO RELATED APPLICATION This application is a continuation of application Ser. No. 62,433, filed Aug. 14, 1970, now abandoned.

BACKGROUND OF THE INVENTION" 1. Field of the Invention The invention is in the field of fasteners and more particularly the invention relates to fasteners suitable for securing panel structures.

2. Description of the Prior Art Honeycomb wall construction is increasingly used in various industries such as airframes, interior structures, mobile homes and the like. Normally, the honeycomb is required to be attached to support structure. The typical fastener that has heretofore been utilized comprises an enlarged head which can be flush mounted in the panel to be secured having a threaded bolt extending therefrom through the panel and into the honeycomb. A second nut piece engages the opposite surface of the structure and is threaded to the bolt. By tightening the members relative to each other the panel is secured to the honeycomb. It is important, however, to lock the nut member relative to the bolt since vibrational energy encountered in an airplane or other moving structures, particularly, tend to loosen the pieces causing eventual separation. The effect of the vibrational energy is particularly felt when the preload on the members is lost.

In the past, the fastener members have often been secured to each other merely by significant tightening to achieve such a preload. This, however, as indicated, is not always satisfactory once the preload is lost. Thus other means have been introduced to secure a locking to prevent the two members from separating. In one prior embodiment locking is affected by compressing or deforming the threads on the nut or outer member. This, of course, affects the overall thread efficiency and the load distribution on the fastener. Further, it is difficult to control the force, thus generated by the thread system which often places undue stress on the skin surfaces of the honeycomb.

A further approach to securing a locking n the members of the fastener to each other has been through the utilization of a separate locking collar or ring which is inserted and seated within the head of the nut member. In a separate step, the locking ring is forced into position within the head portion of the nut tightly securing it to the bolt. This requires an extra step in the process and adds a further piece to the assembly.

Another disadvantage of prior fasteners, particularly for some applications, is that in pulling or moving one member toward or relative to another in order to secure tightening on the thread of the bolt, the head of the bolt is rotated relative to the panel or skin adjacent thereto. This can cause a wearing or deformation of the adjacent material as well as creating undesirable unpredictable frictional resistance to the turning bolt.

SUMMARY OF THE INVENTION The fastener device of this invention comprises a first piece having an enlarged head for disposition in or adjacent to the first panel or sheet. This piece has an integrally formed cylindrical hollow sleeve portion extending from the head for disposition through the hole provided in the panel to be secured. Affixed to the first piece is a through-bolt which extends from the head of the first piece through and past the hollow sleeve portion toward a second panel or surface to be secured. A second piece of the fastener comprises an enlarged head and an integrally formed hollow sleeve portion. When the fastener is assembled to secure the two pieces together the hollow sleeve portion of the second piece surrounds and is in engagement with the extended through-bolt affixed to the first piece with the sleeve portion of the second piece extending toward the sleeve portion of the first piece. The through-bolt has a peripheral groove formed therein located between the head of the first piece and the ends of the bolt. Upon moving the second piece toward the first piece to secure the panels or surfaces together, the sleeve portion of the first piece causes the sleeve portion of the second piece to be at least partially deformed and to collapse inwardly into the peripheral groove formed'on the through-bolt so as to lock the second piece to the through-bolt. In one preferred embodiment of the invention the through-bolt has a threaded shank and a portion of the sleeve of the second piece is internally threaded so as to engage the through-bolt. In an additional embodiment of the invention, the through-bolt is rotatably affixed to the first piece such that the through-bolt can be rotated by a suitable tool without causing rotation of the head portion of the first piece in the hole in which it is disposed in a panel or surface. In a further embodiment of the invention the sleeve portion of the first piece affixed to the through-bolt is deformed radially outwardly to engage a stepped portion in the hole while the sleeve portion of the second piece is deformed inwardly to engage the peripheral groove in the through-bolt. It is believed that the invention will be further understood from the following detailed description and drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. la-lc are pictorial representations of a sequence of installation steps in using a first embodiment of a fastener of the invention. 7

FIGS. 2a-2c disclose a sequence of installation steps in using a second embodiment of a fastener of the invention.

FIG. 3 is a cross-sectional plan view of a third embodiment of the fastener of this invention.

FIG. 4 is a cross-sectional plan view of a fourth embodiment of the fastener of this invention.

FIG. 5 is a cross-sectional plan view ofa fifth embodiment of the fastener of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to FIGS. la-lc there is seen an assembly ofa first device of this invention which is comprised ofa first piece 11 having an enlarged head portion 13 suitable for flush mount of the piece on a surface. The head 13 is of hollow construction and integrally form ed therewith is a hollow cylindrical sleeve 15. Seated within the piece 11 is a through member in the form of a through-bolt 17 having an enlarged head 19 seated within a notched portion 21 of the head 13 and secured thereto by deformed portion 23 on the outer surface of the head as by staking, rolling, bending and the like. The through-bolt extends from its head 19 seated within the first piece 11 to an end thereof 25 and is threaded at 27 or on a portion thereof extending from the end 25 back toward the first piece 11 terminating at a point approximately medianly disposed between the end 25 and the head. In the remaining unthreaded portion of the through-bolt there is formed a peripheral locking groove 29.

Mounted on the through-bolt 17 is a second piece 31 having an enlarged head 33 which can be similar to the head 13 of the first piece 11 but as seen in this embodiment can have a smaller outer diameter. The second piece 31 is also of a hollow construction having an internally threaded portion 35 which engages the threads 27 of the through-bolt. In this particular embodiment of the device the second piece 31 is provided with a sleeve portion 37 extending from the head 33 which has an outer diameter larger than the diameter of the sleeve portion 15 of the first piece 11. The sleeve 37 is then stepped down into a reduced portion 39 which has a diameter essentially equivalent to the diameter of sleeve portion 15. Portion 39 terminates at a chamfered end 41. The sleeve portions 37 and 39 of the second piece have a difference in diameter 43 which is essentially equivalent to the thickness 45 of the sleeve portion 15 of the first piece. An installation tool schematically shown as 44 grips the threaded portion 27 of the through-bolt in a manner to be described and engages head 33 of the second piece or nut 31 with prongs 46.

FIGS. 1a-1c disclose a sequence for assembling panel structures utilizing the fastener device of this invention. Two panels, 47 and 49, are disposed on opposite sides of a center core 51 which may be honeycomb or the like. Each panel has a counterbore portion 53 and 55 respectively in which the head portions 33 and 13 of the device can be seated. Utilizing the particular device in this embodiment a hole 56 is drilled through panel 47 to accommodate the outer diameter of enlarged sleeve portion 37 thereof. The same diameter hole is drilled partially through the center structure 51 at 57 terminating or stepping inwardly in a reduced portion 59 which corresponds to the outer diameter of sleeve portion 15 of the first piece 11. Thus in effect the hole through the center reinforcing structure 51 is stepped, having two diameters, one to accommodate the enlarged diameter portion 37 of the second piece 31 and the remaining portion to accommodate the outerdiameter of the sleeve portion 15, as particularly shown in FIG. Ia. A hole 60, corresponding in diameter to reduced portion 59 is drilled in panel 47 and opens into counterbore 55.

The head portion 33 of the second piece 31 is seated within the corresponding opening 53 in panel 47 while the installation tool 44 is seated by prongs 46 engaging corresponding recesses (not shown) provided in the head 33 serving to prevent rotation of nut 31 while the tool rotates through-bolt 17. Upon rotating the through-bolt 17 with the tool 44, the first piece 11 is caused to move inwardly toward the second piece 31 and seat within its hole 60 and counterbore 55 to the position shown in FIG. 1b. In this position, the chamfered portion 41 of the sleeve portion 39 of the second piece or nut 31 forces the sleeve 15 of the first piece 11 to deform outwardly to fill the enlarged diameter of hole 57 in the center structure 51. Simultaneously, the

I reduced portion 39 of'the sleeve of the second piece 31 is deformed and curves inwardly into the peripheral groove 29 of the through-bolt 17 and then engages the through-bolt 17 and is deformed and curved so that a portion extends axially along the through-bolt 17, occupying an annular, axially extending space between the through-bolt 17 and portion 39. Upon further rotation of the through-bolt 17 the panel 49 and center core 51 and panel 47 are'drawn together, respectively, and sleeves and 39 are further deformed to a final position as seen in FIG. 1c. The through-bolt breaks off at a predetermined torque to assure proper clamp-up of the device. The fracture point is located below or flush with the head 33 ofpiece 31 as seen in FIG. 1c.

The resulting structure as seen in FIG. It provides a locking of the second piece 31 to the through-bolt where the sleeve portion 39, which is of substantially constant wall thickness is deformed at 62 into the peripheral groove 29. The sleeve portion 39 has two deformed portions along its length, and at least a portion of its outer surface is adjacent the inner surface of sleeve 15, being contiguous as shown. Thus even with vibrational energy or reduction of the preload stress on the through-bolt, it is not possible for the piece 31 to significantly move out of its position. A further feature of the embodiment in this figure is that the first piece 11 is also locked in place due to the expansion of the sleeve portion 15 within the enlarged or stepped diameter section 57 of the intermediate piece 51 thereby creating a second or redundant lock for the system.

The pieces 11 and 31 can be made out of material such as an alloy steel or other reasonably ductile material. In the particular embodiment shown in FIGS. Ia-lc it is preferred that the thickness of the sleeve portion 15 of the first piece 11 be equal to or even less than the thickness of the reduced portion 39 of the sleeve of the second piece 31, in order to ensure deformation of sleeve 15 to the enlarged diameter within the area 57.

Turning to FIGS. 2a-2c there is seen an additional second embodiment'of the invention. In this embodiment a panel 61 is affixed to one side of a honeycomb structure 63. In this embodiment the second nut-type member 31 is of essentially the same construction as that shown and described in FIGS. la-lc. A throughbolt 65 is essentially the same as that disclosed in the previous embodiment except that the head portion 66 is of a slightly different configuration but once again allowing it to be locked to but rotative relative to a first member 67.

The difference in this embodiment is in the member 67 in which the through-bolt 65 is seated. In this embodiment there does not exist a stepped hole through the panel 63 which of course is more difficult to achieve than a straight or single diameter hole. Thus in this particular embodiment, the outer diameter of the sleeve portion 69 of the member 67 is the same as the enlarged outer diameter portion 37 of the sleeve of member 31. However, the thickness of the sleeve portion 69 is thicker than in the previous embodiment, and in fact is preferably thicker than the reduced diameter portion 39 of second piece 31. The reason for the difference in thickness between portions 69 and 39 is that the deformation occurs only in portion 39 and it is forced into a peripheral groove 71 in the through-bolt 65 in the annular space between it and sleeve portion 69, the portion 39 being deformed inwardly, and also deformed so that it extends axiallyin the annular space. There is no deformation in portion 69. Thus the resulting structure seen in FIG. 3c has a constant outer diameter along the sleeves and between the enlarged heads 73 and 33 of the first and second pieces respectively. In other words as can be seen from FIG. 2b where the two members 31 and 67 are initially brought into contact, there is no outward expansion of the sleeve portion 69 of the member 67. Thus in the particular embodiment of FIGS. 2a-2c there is a locking of member 31 to the through-bolt 65 resulting from its engagement by the deformed sleeve with the peripheral groove 71 of the through-bolt.

It can be most readily appreciated from the particular embodiment shown in FIGS. 2a-2c that where an end (head 73) of the fastener is in contact with the thin skin 75 of the honeycomb panel structure 63, the lack of rotational movement of the head 73 during the fastening operation could be advantageous. This highlights a feature of the invention where the through-bolt 65 is rotatably attached to the first member 67, thus permitting rotation of the through-bolt without corresponding rotation of head 73 against skin 75.

FIG. 3 is a cross-sectional view of an embodiment of this invention where a through-bolt 77 is integrally formed with a head 79 which serves as the head of the first member. A tubular sleeve 81 surrounds the through-bolt 77 and is preferably closely fitted thereon adjacent the head portion 79 and extending along a portion of the length thereof covering a peripheral groove 85 on the through-bolt. The construction of the embodiment of FIG. 3 is essentially the same construction and operates in the same manner as that shown in FIGS. 2a-2c except that rotational motion will be impartedto head 79 since it is integrally formed with the through-bolt 77. This embodiment is suitable where low preloads avoid the detrimental affects from head rotation against the structure 87.

FIG. 4 depicts an embodiment of the invention utilizing a non-threaded pull through-member. Further, the embodiment illustrates an' arrangement where the heads on either side of the fastener are not mounted flush with the pieces or surfaces secured thereby. The figure is divided into two portions with the portion to the left hand side of the center line 93 indicating the initial position of the fastener element, while on the right hand side of the center line 93 the fastener is shown in a secured position holding together the two surfaces or plates 95 and 97.

In this embodiment an enlarged head 99 is provided adjacent surface 97. The head 99 has rigidly affixed thereto a through-member 101. The through-member 101 has a reduced diameter portion 102 adjacent the head 99 within which is seated a portion of a sleeve 103 which surrounds the stem portion of the throughmember extending from the head 99 through the surfaces 97 and 95. The through-member 101 has a peripheral groove 105 formed medially thereon with-the walls of the stem tapering to a reduced diameter portion forming the groove 105.

A second piece, 107, has an enlarged head, 109, and a sleeve portion 111 which surrounds the throughmember 101 adjacent plate 95. A tool is placed on the through-member 101 abovethe head 109 of piece 107 and the piece 107 is forced downwardly toward the sleeve 103 to a position shown on the right hand of the center line 93 where upon engagement with the tapered end of sleeve 103 the sleeve 111 of piece 107 is deformed inwardly to conform and surround peripheral groove 105 thereby locking the piece 107 relative to the through-member 101. The tapered walls leading to the groove permit transition of the sleeves 111 and 103 leading to and from the groove area. After the deformation step, the pull through-member 101 is snapped off at 113 to be flush with the head portion 109 of piece 107.

As can be seen, this embodiment embraces the concept of the invention; however, the through-member 101 is unthreaded and the second piece 107 moves in sliding engagement with the bolt stem as compared to any rotary action or force where threaded engagement is employed as in the previous embodiments.

Turning now to FIG. 5 there is seen an embodiment of the invention wherein a pull through-member 115 similar to that shown in FIG. 4 is utilized. However, in this embodiment, the concept of the invention is seen utilized for blind hole applications. Head 117 of the through-bolt 115 has an outer diameter slightly smaller or essentially equivalent to the diameter of the hole 119 in members 121 and 123 through which the pulling stem is inserted to secure the members to each other as shown. The diameter of the main portion of the through-member 115, however, is smaller than the diameter of the hole allowing for an elongated sleeve 125 to be inserted completely through the hole 119 to engage the underside 127 of the head 117. Sleeve 125 has an enlarged head 129 thereon which will serve to engage the member 121 when driven on the throughmember 115 toward head 117. The sleeve portion 125 has a peripheral notch 131 thereon.

The operation of the particular device shown is a two-step operation, the first step requiring the throughmember 115 to be pulled upward into the hole 119 to crimp sleeve portion 125 adjacent the head 117 as shown on the right hand side of the center line 133 to provide an enlarged portion 135 engaging member 123. The next operation requires the head 129 on the sleeve 125 to be driven downwardly toward head 117 breaking at notch 131 and being forced into a peripheral groove 137 provided on the through-member 115 in the manner disclosed as in FIG. 4. Thus it can be seen that the embodiment of FIG. 5 is similar to that shown in FIG. 4 in that a non-threaded throughmember is utilized and the portion of the sleeve is forced into a peripheral groove in the same manner. However, the present embodiment also shows the utilization of this concept for blind applications.

In the embodiment of the invention utilizing threaded engagement between the through-bolt and second piece mounted thereon, the locking of the piece to the peripheral groove prevents disassembly of the load carrying threads. In the non-threaded embodiments of FIGS. 4 and 5, the locking to the peripheral groove provides the load carrying mechanism for the fastener in addition to the disassembly locking function.

I claim:

1. In combination;

a first workpiece having a hole provided therethrough,

a second piece fastened to said workpiece having a corresponding hole therethrough and coalignable with said hole in the first workpiece to provide a continuous hole,

a fastener for securing said second piece to said first workpiece comprising:

,a first member having a head portion and a cylindria through-member extending from said head of said first member within and beyond said sleeve, said through-member having a reduced outer diameter extending axially along a portion intermediate of the length thereof thereby providing an elongated peripheral groove therein such that the groove is disposed within the continuous hole, and is radially inwardly of and axially coextensive with at least a portion of the hollow sleeve of the first member to provide an annular, axially extending space therebetween,

second hollow member disposed on said throughmember having a head portion and a cylindrical sleeve extending from said head toward an opposite end adjacent said sleeve portion of said first member, said second member having an inner diameter extending from said opposite end along at least a portion of the length thereof, the innerdiameter being greater than the diameter of the peripheral groove, said sleeve adjacent said head being radially outwardly of said through-member and extending toward the head portion of said first member, a deformed portion of said second member sleeve curving and extending inwardly into said peripheral groove of said through-member and further curving and extending axially within said annular space between said through-member and said sleeve of said first member, said deformed portion being of substantially constant wall thickness, the outer surface of said second member sleeve having an axially extending portion adjacent the inner surface of the first member sleeve,

said head portions each engaging a said workpiece,

and

means on at least one of said hollow members for causing inward deflection of said second member sleeve during assembly.

2. The fastener of claim 1 wherein:

the sleeve of said members is integrally formed with said head portion.

3. The fastener of claim 2 wherein:

the through-member is rotatably affixed to said first member.

4. The fastener of claim 1 wherein:

said through-member has external threads thereon and comprises a through-bolt,

the second hollow member is internally threaded,

and

a portion of said through-bolt engaged by said second member is correspondingly threaded to achieve threaded rotation engagement between said second member and said through bolt.

5. The fastener of claim 1 wherein:

the head portion of said first member is integrally formed on said through-member and said sleeve is a separate piece surrounding the through-bolt.

6. The fastener of claim 5 wherein:

the sleeve of said first member is initially formed in tegrally with the sleeve of said second member, a peripheral notch being provided in said integral sleeves at the point where they are joined.

7. The fastener of claim 1 further comprising:

providing the two sleeves with relative diameters and thicknesses such that the sleeve of said first member is deformed radially outwardly concurrent with the deformation of the second sleeve along the portion of said sleeves forced into contact with each other.

8. The fastener of claim 7 wherein:

a portion of the sleeve of said second member immediately extending from the head thereof has a larger outer diameter than a remaining reduced diameter portion of the sleeve.

9. The fastener of claim 8 wherein:

the outer diameter of the sleeve of said first member is less than the larger diameter portion of the sleeve of said second member. 

1. In combination; a first workpiece having a hole provided therethrough, a second piece fastened to said workpiece having a corresponding hole therethrough and coalignable with said hole in the first workpiece to provide a continuous hole, a fastener for securing said second piece to said first workpiece comprising: a first member having a head portion and a cylindrical hollow sleeve extending therefrom seated in the continuous hole, a through-member extending from said head of said first member within and beyond said sleeve, said through-member having a reduced outer diameter extending axially along a portion intermediate of the length thereof thereby providing an elongated peripheral groove therein such that the groove is disposed within the continuous hole, and is radially inwardly of and axially coextensive with at least a portion of the hollow sleeve of the first member to provide an annular, axially extending space therebetween, a second hollow member disposed on said through-member having a head portion and a cylindrical sleeve extending from said head toward an opposite end adjacent said sleeve portion of said first member, said second member having an inner diameter extending from said opposite end along at least a portion of the length thereof, the inner diameter being greater than the diameter of the peripheral groove, said sleeve adjacent said head being radially outwardly of said through-member and extending toward the head portion of said first member, a deformed portion of said second member sleeve curving and extending inwardly into said peripheral groove of said throughmember and further curving and extending axially within said annular space between said through-member and said sleeve of said first member, said deformed portion being of substantially constant wall thickness, the outer surface of said second member sleeve having an axially extending portion adjacent the inner surface of the first member sleeve, said head portions each engaging a said workpiece, and means on at least one of said hollow members for causing inward deflection of said second member sleeve during assembly.
 2. The fastener of claim 1 wherein: the sleeve of said members is integrally formed with said head portion.
 3. The fastener of claim 2 wherein: the through-member is rotatably affixed to said first member.
 4. The fastener of claim 1 wherein: said through-member has external threads thereon and comprises a through-bolt, the second hollow memBer is internally threaded, and a portion of said through-bolt engaged by said second member is correspondingly threaded to achieve threaded rotation engagement between said second member and said through-bolt.
 5. The fastener of claim 1 wherein: the head portion of said first member is integrally formed on said through-member and said sleeve is a separate piece surrounding the through-bolt.
 6. The fastener of claim 5 wherein: the sleeve of said first member is initially formed integrally with the sleeve of said second member, a peripheral notch being provided in said integral sleeves at the point where they are joined.
 7. The fastener of claim 1 further comprising: providing the two sleeves with relative diameters and thicknesses such that the sleeve of said first member is deformed radially outwardly concurrent with the deformation of the second sleeve along the portion of said sleeves forced into contact with each other.
 8. The fastener of claim 7 wherein: a portion of the sleeve of said second member immediately extending from the head thereof has a larger outer diameter than a remaining reduced diameter portion of the sleeve.
 9. The fastener of claim 8 wherein: the outer diameter of the sleeve of said first member is less than the larger diameter portion of the sleeve of said second member. 